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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * drivers/power/process.c - Functions for starting/stopping processes on | |
3 | * suspend transitions. | |
4 | * | |
5 | * Originally from swsusp. | |
6 | */ | |
7 | ||
8 | ||
9 | #undef DEBUG | |
10 | ||
1da177e4 | 11 | #include <linux/interrupt.h> |
1a8670a2 | 12 | #include <linux/oom.h> |
1da177e4 LT |
13 | #include <linux/suspend.h> |
14 | #include <linux/module.h> | |
02aaeb9b | 15 | #include <linux/syscalls.h> |
7dfb7103 | 16 | #include <linux/freezer.h> |
be404f02 | 17 | #include <linux/delay.h> |
a0a1a5fd | 18 | #include <linux/workqueue.h> |
1e73203c | 19 | #include <linux/kmod.h> |
bb3632c6 | 20 | #include <trace/events/power.h> |
1da177e4 LT |
21 | |
22 | /* | |
23 | * Timeout for stopping processes | |
24 | */ | |
957d1282 | 25 | unsigned int __read_mostly freeze_timeout_msecs = 20 * MSEC_PER_SEC; |
1da177e4 | 26 | |
839e3407 | 27 | static int try_to_freeze_tasks(bool user_only) |
1da177e4 | 28 | { |
1da177e4 | 29 | struct task_struct *g, *p; |
11b2ce2b RW |
30 | unsigned long end_time; |
31 | unsigned int todo; | |
a0a1a5fd | 32 | bool wq_busy = false; |
f7b382b9 | 33 | ktime_t start, end, elapsed; |
18ad0c62 | 34 | unsigned int elapsed_msecs; |
dbeeec5f | 35 | bool wakeup = false; |
18ad0c62 | 36 | int sleep_usecs = USEC_PER_MSEC; |
438e2ce6 | 37 | |
f7b382b9 | 38 | start = ktime_get_boottime(); |
3e1d1d28 | 39 | |
957d1282 | 40 | end_time = jiffies + msecs_to_jiffies(freeze_timeout_msecs); |
a0a1a5fd | 41 | |
839e3407 | 42 | if (!user_only) |
a0a1a5fd TH |
43 | freeze_workqueues_begin(); |
44 | ||
be404f02 | 45 | while (true) { |
11b2ce2b | 46 | todo = 0; |
1da177e4 | 47 | read_lock(&tasklist_lock); |
a28e785a | 48 | for_each_process_thread(g, p) { |
839e3407 | 49 | if (p == current || !freeze_task(p)) |
d5d8c597 RW |
50 | continue; |
51 | ||
5d8f72b5 | 52 | if (!freezer_should_skip(p)) |
ba96a0c8 | 53 | todo++; |
a28e785a | 54 | } |
1da177e4 | 55 | read_unlock(&tasklist_lock); |
a0a1a5fd | 56 | |
839e3407 | 57 | if (!user_only) { |
a0a1a5fd TH |
58 | wq_busy = freeze_workqueues_busy(); |
59 | todo += wq_busy; | |
60 | } | |
61 | ||
be404f02 | 62 | if (!todo || time_after(jiffies, end_time)) |
6161b2ce | 63 | break; |
be404f02 | 64 | |
a2867e08 | 65 | if (pm_wakeup_pending()) { |
dbeeec5f RW |
66 | wakeup = true; |
67 | break; | |
68 | } | |
69 | ||
be404f02 TH |
70 | /* |
71 | * We need to retry, but first give the freezing tasks some | |
18ad0c62 CC |
72 | * time to enter the refrigerator. Start with an initial |
73 | * 1 ms sleep followed by exponential backoff until 8 ms. | |
be404f02 | 74 | */ |
18ad0c62 CC |
75 | usleep_range(sleep_usecs / 2, sleep_usecs); |
76 | if (sleep_usecs < 8 * USEC_PER_MSEC) | |
77 | sleep_usecs *= 2; | |
be404f02 | 78 | } |
3e1d1d28 | 79 | |
f7b382b9 AJ |
80 | end = ktime_get_boottime(); |
81 | elapsed = ktime_sub(end, start); | |
82 | elapsed_msecs = ktime_to_ms(elapsed); | |
438e2ce6 | 83 | |
6161b2ce | 84 | if (todo) { |
35536ae1 MH |
85 | pr_cont("\n"); |
86 | pr_err("Freezing of tasks %s after %d.%03d seconds " | |
a0a1a5fd | 87 | "(%d tasks refusing to freeze, wq_busy=%d):\n", |
dbeeec5f | 88 | wakeup ? "aborted" : "failed", |
18ad0c62 | 89 | elapsed_msecs / 1000, elapsed_msecs % 1000, |
a0a1a5fd TH |
90 | todo - wq_busy, wq_busy); |
91 | ||
7b776af6 RL |
92 | if (wq_busy) |
93 | show_workqueue_state(); | |
94 | ||
6c83b481 RW |
95 | if (!wakeup) { |
96 | read_lock(&tasklist_lock); | |
a28e785a | 97 | for_each_process_thread(g, p) { |
6c83b481 RW |
98 | if (p != current && !freezer_should_skip(p) |
99 | && freezing(p) && !frozen(p)) | |
100 | sched_show_task(p); | |
a28e785a | 101 | } |
6c83b481 RW |
102 | read_unlock(&tasklist_lock); |
103 | } | |
438e2ce6 | 104 | } else { |
35536ae1 | 105 | pr_cont("(elapsed %d.%03d seconds) ", elapsed_msecs / 1000, |
18ad0c62 | 106 | elapsed_msecs % 1000); |
6161b2ce PM |
107 | } |
108 | ||
e7cd8a72 | 109 | return todo ? -EBUSY : 0; |
11b2ce2b RW |
110 | } |
111 | ||
112 | /** | |
2aede851 | 113 | * freeze_processes - Signal user space processes to enter the refrigerator. |
2b44c4db CC |
114 | * The current thread will not be frozen. The same process that calls |
115 | * freeze_processes must later call thaw_processes. | |
03afed8b TH |
116 | * |
117 | * On success, returns 0. On failure, -errno and system is fully thawed. | |
11b2ce2b RW |
118 | */ |
119 | int freeze_processes(void) | |
120 | { | |
e7cd8a72 | 121 | int error; |
11b2ce2b | 122 | |
247bc037 | 123 | error = __usermodehelper_disable(UMH_FREEZING); |
1e73203c RW |
124 | if (error) |
125 | return error; | |
126 | ||
2b44c4db CC |
127 | /* Make sure this task doesn't get frozen */ |
128 | current->flags |= PF_SUSPEND_TASK; | |
129 | ||
a3201227 TH |
130 | if (!pm_freezing) |
131 | atomic_inc(&system_freezing_cnt); | |
132 | ||
068765ba | 133 | pm_wakeup_clear(); |
35536ae1 | 134 | pr_info("Freezing user space processes ... "); |
a3201227 | 135 | pm_freezing = true; |
ebb12db5 | 136 | error = try_to_freeze_tasks(true); |
2aede851 | 137 | if (!error) { |
247bc037 | 138 | __usermodehelper_set_disable_depth(UMH_DISABLED); |
c32b3cbe | 139 | pr_cont("done."); |
2aede851 | 140 | } |
35536ae1 | 141 | pr_cont("\n"); |
2aede851 RW |
142 | BUG_ON(in_atomic()); |
143 | ||
c32b3cbe MH |
144 | /* |
145 | * Now that the whole userspace is frozen we need to disbale | |
146 | * the OOM killer to disallow any further interference with | |
147 | * killable tasks. | |
148 | */ | |
149 | if (!error && !oom_killer_disable()) | |
150 | error = -EBUSY; | |
151 | ||
74070542 MH |
152 | /* |
153 | * There is a hard to fix race between oom_reaper kernel thread | |
154 | * and oom_killer_disable. oom_reaper calls exit_oom_victim | |
155 | * before the victim reaches exit_mm so try to freeze all the tasks | |
156 | * again and catch such a left over task. | |
157 | */ | |
158 | if (!error) { | |
159 | pr_info("Double checking all user space processes after OOM killer disable... "); | |
160 | error = try_to_freeze_tasks(true); | |
161 | pr_cont("\n"); | |
162 | } | |
163 | ||
03afed8b TH |
164 | if (error) |
165 | thaw_processes(); | |
2aede851 RW |
166 | return error; |
167 | } | |
168 | ||
169 | /** | |
170 | * freeze_kernel_threads - Make freezable kernel threads go to the refrigerator. | |
03afed8b | 171 | * |
379e0be8 SB |
172 | * On success, returns 0. On failure, -errno and only the kernel threads are |
173 | * thawed, so as to give a chance to the caller to do additional cleanups | |
174 | * (if any) before thawing the userspace tasks. So, it is the responsibility | |
175 | * of the caller to thaw the userspace tasks, when the time is right. | |
2aede851 RW |
176 | */ |
177 | int freeze_kernel_threads(void) | |
178 | { | |
179 | int error; | |
11b2ce2b | 180 | |
35536ae1 MH |
181 | pr_info("Freezing remaining freezable tasks ... "); |
182 | ||
a3201227 | 183 | pm_nosig_freezing = true; |
ebb12db5 | 184 | error = try_to_freeze_tasks(false); |
2aede851 | 185 | if (!error) |
35536ae1 | 186 | pr_cont("done."); |
7f33d49a | 187 | |
35536ae1 | 188 | pr_cont("\n"); |
2aede851 | 189 | BUG_ON(in_atomic()); |
7f33d49a | 190 | |
03afed8b | 191 | if (error) |
379e0be8 | 192 | thaw_kernel_threads(); |
b842ee57 | 193 | return error; |
1da177e4 LT |
194 | } |
195 | ||
6cd8dedc | 196 | void thaw_processes(void) |
1da177e4 LT |
197 | { |
198 | struct task_struct *g, *p; | |
2b44c4db | 199 | struct task_struct *curr = current; |
1da177e4 | 200 | |
bb3632c6 | 201 | trace_suspend_resume(TPS("thaw_processes"), 0, true); |
a3201227 TH |
202 | if (pm_freezing) |
203 | atomic_dec(&system_freezing_cnt); | |
204 | pm_freezing = false; | |
205 | pm_nosig_freezing = false; | |
206 | ||
6cd8dedc TH |
207 | oom_killer_enable(); |
208 | ||
35536ae1 | 209 | pr_info("Restarting tasks ... "); |
6cd8dedc | 210 | |
4320f6b1 | 211 | __usermodehelper_set_disable_depth(UMH_FREEZING); |
6cd8dedc TH |
212 | thaw_workqueues(); |
213 | ||
1da177e4 | 214 | read_lock(&tasklist_lock); |
a28e785a | 215 | for_each_process_thread(g, p) { |
2b44c4db CC |
216 | /* No other threads should have PF_SUSPEND_TASK set */ |
217 | WARN_ON((p != curr) && (p->flags & PF_SUSPEND_TASK)); | |
a5be2d0d | 218 | __thaw_task(p); |
a28e785a | 219 | } |
1da177e4 | 220 | read_unlock(&tasklist_lock); |
7f33d49a | 221 | |
2b44c4db CC |
222 | WARN_ON(!(curr->flags & PF_SUSPEND_TASK)); |
223 | curr->flags &= ~PF_SUSPEND_TASK; | |
224 | ||
1e73203c RW |
225 | usermodehelper_enable(); |
226 | ||
1da177e4 | 227 | schedule(); |
35536ae1 | 228 | pr_cont("done.\n"); |
bb3632c6 | 229 | trace_suspend_resume(TPS("thaw_processes"), 0, false); |
1da177e4 LT |
230 | } |
231 | ||
181e9bde RW |
232 | void thaw_kernel_threads(void) |
233 | { | |
234 | struct task_struct *g, *p; | |
235 | ||
236 | pm_nosig_freezing = false; | |
35536ae1 | 237 | pr_info("Restarting kernel threads ... "); |
181e9bde RW |
238 | |
239 | thaw_workqueues(); | |
240 | ||
241 | read_lock(&tasklist_lock); | |
a28e785a | 242 | for_each_process_thread(g, p) { |
181e9bde RW |
243 | if (p->flags & (PF_KTHREAD | PF_WQ_WORKER)) |
244 | __thaw_task(p); | |
a28e785a | 245 | } |
181e9bde RW |
246 | read_unlock(&tasklist_lock); |
247 | ||
248 | schedule(); | |
35536ae1 | 249 | pr_cont("done.\n"); |
181e9bde | 250 | } |